This invention relates generally to food processing, particularly meat processing and improving the tenderness of meat. More particularly, the invention relates to methods and apparatuses for improving meat tenderness through manipulation of an animal carcass or portions thereof prior to rigor mortis, including separation of one or more vertebrae of a carcass.
Consumers of meat products generally prefer tender meat. Inadequate tenderness is therefore an important quality control concern for meat producers, particularly red meat producers. In addition, a large amount of variation may exist in the tenderness of meat cuts at retail and food service levels. Improvements in the tenderness of meat products would allow a meat producer to increase both the quantity of meat products sold and the price at which those products are sold.
A number of factors influence the tenderness of meat, including genetics, the age of the animal at slaughter, the breed of the animal, the animal's health, whether the animal is range fed or fed cereal grains, the amount of growth hormones administered to the animal, and the climate. Genetics may account for around thirty percent of the influence on meat tenderness, with other factors accounting for the remaining seventy percent. Older animals typically produce tougher, less tender meat than do younger animals. If an animal is in poor health, the meat resulting from that animal may be less tender. If an animal receives a large amount of growth hormones during the animal's life, the meat resulting from that animal may be less tender. Certain types of cattle, such as Brahman, generally produce less tender meat than do other cattle. Cattle with larger hump heights generally are more likely to be Brahman cattle or have a hereditary link to Brahman cattle, and therefore typically produce less tender meat.
A variety of methods have been used in an attempt to improve the tenderness of red meat products, including electrical stimulation of pre-rigor carcasses, chemical injections, maceration, and various feeding techniques. Methods involving chemical injections have been devised that may be conducted on animals prior to slaughter and also on carcasses after slaughter. Some of these techniques involve injections of brine solutions, such as calcium chloride, in an effort to increase tenderness. Other methods involve the injection of enzymes or chemicals into an animal or a carcass to improve meat tenderness. Dietary supplements include the administration of Vitamin D or its analogs or derivatives to livestock, as is described in U.S. Pat. No. 5,968,565 to Owens et al. Maceration techniques commonly involve penetration of the meat with needles or the like to increase tenderness.
The methods for tenderizing meat discussed above have a number of disadvantages. These methods are generally expensive and labor intensive, and hence are not viable for commercial production of meat products. Expenses include labor costs for injections, feed supplements, maceration techniques, as well as equipment and chemical, enzyme, or feed supplement costs. In addition, the consuming public may be concerned with the safety of the use of chemicals, enzymes, or feed supplements. Further, the effectiveness of the above methods may be questioned and the administration of these techniques may be complex to control.
Postmortem aging of meat is another common technique for tenderizing meat. Meat may be aged for a variable period of time (in the area of from three to ninety-nine days) to increase meat tenderness, depending on the type of animal and the cut of meat. Aging increases tenderness because enzymatic degradation of muscle fibers occurs. Aging of meat, however, has disadvantages. First, the longer meat is aged, the larger the amount of moisture that is lost from the meat, thus influencing the palatability of the meat. Second, there is a storage cost for aging meat in commercial meat production. Third, aging of meat influences the shelf life of the meat product. If meat is aged for a large amount of time, for instance, the shelf life of the product will decrease, and the meat may also not look as appetizing (the color may be altered) as meat that has not been aged as long.
In addition to those methods discussed above for improving the tenderness of meat, another method described by Claus and Marriot, referred to as the “Tendercut Process” and available on the Internet at <www.fst.vt.edu/files/tendercu.html>, has been proposed to increase the tenderness of beef. In the Tendercut Process, a beef carcass is manipulated after slaughter and prior to rigor mortis. After the beef carcass has been split in half (by sawing the carcass midway through the spinal column to form a left side and a right side), the Tendercut Process involves making one or two detailed cuts. One cut is made between the fourth and fifth sacral vertebrae of the carcass, and involves a complete cut of the sacral vertebrae and all fat, connective tissue, and minor muscles surrounding the wholesale round muscles of the beef carcass. A second cut is made between the twelfth and thirteenth ribs of the carcass, and involves a complete cut of the vertebral column and the spinal processes, as well as all fat, connective tissue, intercostal muscles, and minor muscles surrounding the longissimus dorsi. After the carcass is cut, a separation between bones and tissues in the location of the cut of between 4-6 inches results, thus stretching the muscle prior to rigor mortis to reduce shortening of the muscle fiber during chilling of the carcass.
The Tendercut Process, has a number of disadvantages for the commercial production of meat products. A large number of procedures are required in this process, including sawing the vertebrae with a saw and cutting the minor muscles, fat, and connective tissue with a knife. This method is very time consuming due to the number of knife cuts required, thus requiring a large expenditure for labor if used in a commercial meat production facility. In addition, due to the number and complexity of the saws and cuts that are required, a significant chance of damage to the primary muscles results (those muscles for which stretching is desired to increase tenderness, e.g., the longissimus dorsi and round muscles of beef carcasses). Moreover, this method may alter the appearance of the muscles and fat assigned by the USDA graders (quality and grade) because the location of the cut between the twelfth and thirteenth ribs is the area evaluated for USDA grades. The Tendercut Process has not been adopted widely in commercial processes.
U.S. Pat No. 3,579,716 to Stouffer et al. (“Stoufffer '715”) issued on May 25, 1971, discloses another meat tenderizing method. The Stouffer patent discloses tenderizing a muscle in the following manner: “The backbone—which is visible on the split carcass half—is severed (preferably at several spaced locations), whereby the weight of the carcass half is sufficient to extend and maintain tension on the longissimus muscle during the passage of rigor mortis.” Stouffer '716, col. 4, 11. 21-25. Stouffer '716 also discloses that additional weights may be added to the carcass for further tensioning. When the application for Stouffer '716 was filed in 1969, commercial meat production facilities were vastly different than today. Typically, chains were not used to transport animal carcasses in 1969 and slaughter and production rates were significantly slower than today. Stouffer '716, therefore, does not disclose a tenderizing method that may be readily used in commercial meat production facilities today. In addition, animals, for example, cattle for beef production, were not administered growth hormones in 1969 as is common today. The beef resulting from the carcasses in 1969, therefore, differed in many properties, including tenderness, from beef today, and hence treatment of carcasses today differs from treatment of carcasses in 1969.
A need exists for methods and apparatuses for improving the tenderness of meat that are inexpensive and commercially practical, easy and quick to conduct, not significantly invasive, and that will not raise concerns with the consuming public about additives to meat products.